If you do something like this:
(postmodern::query '(:select 1))
The value (:SELECT 1) is not of type STRING. [Condition of type TYPE-ERROR]
Restarts: 0: [ABORT] Return to SLIME's top level. 1: [TERMINATE-THREAD] Terminate this thread (#<THREAD "repl-thread" {AF37921}>) 0
the slime-repl buffer starts waiting for something (probably some response from the database). When you hit C-c, and select abort, it stops. Afterwards, however, the database connection is lost:
(postmodern::query (:select 1))
Database error: Connection to database server lost. [Condition of type DATABASE-CONNECTION-LOST]
Restarts: 0: [RECONNECT] Try to reconnect. 1: [ABORT] Return to SLIME's top level. 2: [TERMINATE-THREAD] Terminate this thread (#<THREAD "repl-thread" {AF37921}>)
The problem lies probably somewhere deeper than in query. If I have some time, I'll try to investigate it.
Cheers,
-- Richard